It's impossible to say what the traffic is for, if it's incoming connections that are dropped by your computer (or firewall) it's most likely the background noise of the Internet, if it's outgoing connections from your computer it could be traffic related to torrents, Tor, etc.

Use netstat -nao and the task manager to identify which pids are doing what as MrTuxracer said. You can enable viewing the PIDs in the Task Manager by opening the View menu, clicking Select Columns, and then ticking PID (Process Identifier) on.

You can also use the console (cmd.exe) with the following command: tasklist

Check out ProcessHacker http://processhacker.sourceforge.net/Have a look at the network tab to see the ports in use by the different services. The tool is similar to those mentioned above but it has a lot more to offer.

Last edited by Dark_Knight on Fri Jun 15, 2012 9:30 am, edited 1 time in total.